Hi all,
What about this feature? Provide a method of adjust mmc bounce size through
menuconfig
or /sys/block/mmcblk0 at run-time. Which one is better?
Do you have any ideas? Thanks for your advice.
From: Liu Qiang-B32616
Sent: Friday, November 04, 2011 4:54 AM
To: linux-mmc@vger.kernel.org
Cc: c...@laptop.org; Li Yang-R58472; Gala Kumar-B11780; Liu Qiang-B32616; Liu
Qiang-B32616
Subject: [PATCH] [RFC/PATCH] SD/MMC: support adjust bounce buffer size
dynamically in menuconfig
Improve IO throughput according to different controllers.
Make it configuable in menuconfig. Of course, there is another
implement of adjust bounce buffer size at run-time. Like:
echo 262144 /sys/block/mmcblk0/device/bouncesz
This will reinit mmc queue when bounce size is changed.
Which is better?
On powerpc platform, 256KiB will get better perfromance than 64KiB.
I used Sandisk Extreme III Class 6, 4G memory card, tested on P1022DS
with IOzone. P1022DS memory is 1GBytes. Filesystem is ext4.
By default, bounce buffer size is 64KiB,
[root@p1022ds root]# iozone -Rab result -i0 -i1 -r64 -n1g -g2g -f /mnt/ff
KB reclen write rewritereadreread
1048576 64 12794 132603233031731
2097152 64 12301 123821821318239
use 256KiB as bounce buffer size,
[root@p1022ds root]# iozone -Rab result -i0 -i1 -r64 -n1g -g2g -f /mnt/ff
KB reclen write rewritereadreread
1048576 64 18533 190762284123151
2097152 64 17744 179801833318342
Signed-off-by: Qiang Liu qiang@freescale.com
---
drivers/mmc/card/Kconfig |9 +
drivers/mmc/card/queue.c |2 +-
2 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/drivers/mmc/card/Kconfig b/drivers/mmc/card/Kconfig
index 3b1f783..3390154 100644
--- a/drivers/mmc/card/Kconfig
+++ b/drivers/mmc/card/Kconfig
@@ -50,6 +50,15 @@ config MMC_BLOCK_BOUNCE
If unsure, say Y here.
+config MMC_QUEUE_BOUNCESZ
+ int MMC memory card bounce buffer size
+ depends on MMC_BLOCK_BOUNCE
+ range 512 4194304
+ default 65536
+ help
+ Provide a flexible method to adjust bounce buffer size to
+ improve the throughput according to different controller.
+
config SDIO_UART
tristate SDIO UART/GPS class support
help
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index dcad59c..590723f 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -20,7 +20,7 @@
#include linux/mmc/host.h
#include queue.h
-#define MMC_QUEUE_BOUNCESZ 65536
+#define MMC_QUEUE_BOUNCESZ CONFIG_MMC_QUEUE_BOUNCESZ
#define MMC_QUEUE_SUSPENDED(1 0)
--
1.6.4
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